Thunderstorms developed as a cold front interacted with a moist and very unstable air mass over Wisconsin. Many of the storms became severe, with gusts in excess of 60 mph, as they moved across east central Wisconsin. Downed trees and power lines were widespread. At least 50,000 people on the north side of Oshkosh (Winnebago co.) were without electricity for at least part of the evening. A billboard was destroyed when it was blown onto U.S. Highway 41 near Lake Butte des Morts (Winnebago co.). Heavy damage was reported in the Appleton area (Outagamie co.), where at least one tree landed on a car, flag poles were blown down, roofs were torn from at least three houses under construction, a construction trailer was overturned and a semi was blown over on U.S. Highway 441. Silos, sheds, garages and at least three barns were blown down and power was knocked out in Greenville (Outagamie co.) and Freedom (Outagamie co.). The wind tore away parts of the screen at a drive-in movie theater in Freedom. In Ashwaubenon (Brown co.) a twenty unit garage that was under construction was destroyed, by winds estimated near 80 mph, when it was lifted from its concrete slab and thrown at least 100 feet. A pole building was blown down near Cooperstown (Manitowoc co.) and baseball size hail broke windows near Algoma (Kewaunee co.).A tornado touched down in De Pere (Brown co.) and traveled north into Allouez (Brown co.) where it dissipated just north of Heritage Hill State Park.  The tornado's occasional brief touchdowns topped numerous trees. Some of the trees caused damage to buildings and vehicles when they fell, but the tornado caused little direct structural damage to any buildings.

Tornado in BROWN, WISCONSIN
From 13-SEP-05 17:09:00 to 13-SEP-05 17:12:00 (CST)
Location: DE PERE
Tornado F-scale: F0
Property damage: 5K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 13-SEP-05 16:45:00 to 13-SEP-05 17:05:00 (CST)
Location: APPLETON
Magnitude: 65 EG
Property damage: 1.1M
Reported by: NWS STORM SURVEY

Thunderstorm Wind in BROWN, WISCONSIN
From 13-SEP-05 17:15:00 to 13-SEP-05 17:15:00 (CST)
Location: GREEN BAY
Magnitude: 59 MG
Property damage: 50K
Reported by: NWS EMPLOYEE(OFF DUTY)

Thunderstorm Wind in BROWN, WISCONSIN
From 13-SEP-05 17:11:00 to 13-SEP-05 17:11:00 (CST)
Location: ASHWAUBENON
Magnitude: 70 EG
Property damage: 50K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in WINNEBAGO, WISCONSIN
From 13-SEP-05 16:38:00 to 13-SEP-05 16:44:00 (CST)
Location: OSHKOSH WITTMAN FLD
Magnitude: 60 EG
Property damage: 33K
Reported by: NWS EMPLOYEE(OFF DUTY)

Hail in PORTAGE, WISCONSIN
From 13-SEP-05 16:10:00 to 13-SEP-05 16:10:00 (CST)
Location: STEVENS PT
Magnitude: 0.75 
Reported by: AMATEUR RADIO

Hail in KEWAUNEE, WISCONSIN
From 13-SEP-05 16:44:00 to 13-SEP-05 16:44:00 (CST)
Location: ALGOMA
Magnitude: 1.75 
Property damage: 1K
Reported by: GENERAL PUBLIC

Thunderstorm Wind in CALUMET, WISCONSIN
From 13-SEP-05 17:00:00 to 13-SEP-05 17:00:00 (CST)
Location: NEW HOLSTEIN
Magnitude: 50 EG
Reported by: AMATEUR RADIO

Thunderstorm Wind in BROWN, WISCONSIN
From 13-SEP-05 17:11:00 to 13-SEP-05 17:11:00 (CST)
Location: DE PERE
Magnitude: 65 EG
Property damage: 30K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in DOOR, WISCONSIN
From 13-SEP-05 17:22:00 to 13-SEP-05 17:22:00 (CST)
Location: STURGEON BAY
Magnitude: 50 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in SHAWANO, WISCONSIN
From 13-SEP-05 16:12:00 to 13-SEP-05 16:12:00 (CST)
Location: NAVARINO
Magnitude: 52 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in BROWN, WISCONSIN
From 13-SEP-05 17:09:00 to 13-SEP-05 17:09:00 (CST)
Location: WRIGHTSTOWN
Magnitude: 56 EG
Reported by: NWS EMPLOYEE(OFF DUTY)

Thunderstorm Wind in WAUPACA, WISCONSIN
From 13-SEP-05 16:30:00 to 13-SEP-05 16:38:00 (CST)
Location: FREMONT
Magnitude: 52 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 13-SEP-05 17:20:00 to 13-SEP-05 17:20:00 (CST)
Location: COOPERSTOWN
Magnitude: 50 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in KEWAUNEE, WISCONSIN
From 13-SEP-05 16:40:00 to 13-SEP-05 16:40:00 (CST)
Location: CASCO
Magnitude: 52 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in BROWN, WISCONSIN
From 13-SEP-05 17:08:00 to 13-SEP-05 17:08:00 (CST)
Location: HOWARD
Magnitude: 55 EG
Reported by: GENERAL PUBLIC

Thunderstorm Wind in CALUMET, WISCONSIN
From 13-SEP-05 16:54:00 to 13-SEP-05 16:55:00 (CST)
Location: DARBOY
Magnitude: 66 MG
Reported by: GENERAL PUBLIC

Hail in DOOR, WISCONSIN
From 13-SEP-05 16:47:00 to 13-SEP-05 16:47:00 (CST)
Location: FORESTVILLE
Magnitude: 1.75 
Reported by: OFFICIAL NWS OBS.

Thunderstorm Wind in WAUSHARA, WISCONSIN
From 13-SEP-05 16:04:00 to 13-SEP-05 16:04:00 (CST)
Location: PLAINFIELD
Magnitude: 50 EG
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in MANITOWOC, WISCONSIN
From 13-SEP-05 17:15:00 to 13-SEP-05 17:15:00 (CST)
Location: COOPERSTOWN
Magnitude: 55 EG
Reported by: GENERAL PUBLIC

Thunderstorm Wind in OUTAGAMIE, WISCONSIN
From 13-SEP-05 17:05:00 to 13-SEP-05 17:05:00 (CST)
Location: FREEDOM
Magnitude: 65 EG
Reported by: NWS STORM SURVEY